Speed-gearing for bicycles



(No Model!) 2 sheets sheet 1. J. W. BRASPIELD & J. H. JENKINS.

SPEED GEARING FOR BIGYGLES.

Patented Apr. 13, 1897.

[72 veniafeii (No Model.)

2Sheets--Sheet 2. J. W. BRASPIELD & J. H. JENKINS. SPEED GEARING FORBIGYGLES.

Patented Apr. 13, 1897. a amnmilmn a III 1725672 wrest JZ IKBWaQjZeZLZand trifle/agar PATENT FFICE,

JAMES IV. BRASFIELD AND JOSEPH I-I. JENKINS, OF SMITHVILLE, MISSOURI.

SPEED-GEARING FOR BICYCLES.

SPECIFICATION forming part of Letters Patent No. 580,366, dated April13, 1897. Application filed December 26, 1895., Serial No. 573,334. (Nomodel.)

To all 1071/0111, it may concern:

Be it known that we, JAMES W. BRASFIELD and JOSEPH H. J ENKINS, ofSmithville, Clay county, Missouri, have invented certain new and usefulImprovements in Speed-Gearings for Bicycles, of which the following is afull, clear, and exact description, reference being had to theaccompanying drawings, forming a part hereof.

Our invention relates to speed-gearing for bicycles; and our object isto produce mechanism of this character whereby the rider may easily andquickly change the speed by raising or lowering the gear or may throwthe pedals entirely out of gear, by means of such mechanism, with thedrive-wheel of the machine. 13y lowering the gear it is obvious thathills may he climbed with less exertion, but at a diminished speed, andthat when the gear is raised the speed is increased at a correspondingor proportionate expenditure of power.

With these objects in view our invention contemplates in particular aconstruction whereby the machine may be propelled under a low, a medium,or a high degree of power, and consequently at different speeds.

Other objects of the invention will appear in the following descriptionand be pointed out in appended claim.

In the drawings which illustrate the inventi0n,'Figure 1 represents,principally in side elevation, a bicycle embodying our invention. Fig. 2represents, on an enlarged scale, a top plan view of part of the same.Fig. 3 represents a sectional View taken principally on the line at w ofFig. 4. Fig. 4 is a section taken on the line y y of Fig. 3. Fig. 5 is avertical section taken on the line 2 z of Fig. 4.

In the said drawings, 1 designates the wheels of a bicycle.

2 designates the frame. This frame, as shown, is of differentconstruction and configuration from the ordinary bicycle-frame, thoughits precise construction or configuration is immaterial and forms noessential part of our improvement. As shown, the seat braces orstandards 3 are in duplicate and parallel, andthe front braces 4 arealso in duplicate and parallel. (See Fig. 2.) The seat brace or braces 3form a junction with the rear forks 5 in the customary manner.

The front braces 4, however, are preferably coupled at their lower endsto the lower ends of the braces 3 by means of the horizontal parallelsections 6 of the framework, and said sections 4 may in turn beconnected by the cross-brace 4. lel portion 6 of the of the braces 3 and4 and supported rigidly in such position, in any suitable manner, byattachment to the frame is the casing 7', and extending transverselythrough said casing and journaled in the portion 6 of the frame are theshafts 8, 9, and 10. The shaft 8 carries upon one end in the customarymanner a sprocket-wheel 11, and said wheel is 0011- nected by means ofthe sprocket-chain 12 to the small sprocket-wheel13, mounted rigidlyupon the rear or drive wheel of the bicycle. Mounted rigidly in thecustomary manner upon opposite ends of the shaft 9 are the crank-arms14, which are provided with the pedals 15. Keyed rigidly upon the shaft10 within the casing 7 are the comparatively small and large cog-wheels16 and 17, at a suitable distance apart.

1S and 19 designate, respectively, the integrally-formed large and smallcog-wheels, which are mounted so as to slide upon and rotate with theshaft 8. complished by providing said shaft with a longitudinal key orspline 20, which engages a corresponding groove in said wheels 18 and19.

21 and 22 designate similar integrallyformed -cog-whee1s, which aremounted to slide upon and rotate with the shaft 9, and to accomplishthis they are provided with grooves which engage the longitudinal key orspline 23 of said shaft.

24 and 25 design ate parallel rods which are journaled near their upperand lower ends in the top bar of the frame and the casing, and 26designates arms which are mounted rigidly upon their lower ends withinthe casing. Said arms engage openings in the upper ends of the clutches27, and this connection is made positive by set-screws 28, which arecarried by the clutches and impinge upon said arms. Said clutches areforked or of inverted U shape, and their depending arms 29, which arepreferably rounded at their inner sides, as shown in dotted lines, Fig.4, are arranged contiguous to the Arranged between the paralframe andthe lower endsv the top plate of.

This relation is acouter faces of the wheels 18 19 and 21 22. At thelower ends of said arms project inwardly against the outer face of thewheels 18 and 21 and 19 and 22, respectively, the rounded lugs 30 and31, the lugs 31 preferably engaging annular grooves 32 of the smallcogwheels, as shown. As arranged, the arms 26 at the lower ends of therods 24 and 25, by bearin g against the underside of the top plate ofthe casing 7, which top plate is preferably secured by screw-bolts,preventany upward movement of the said rods, (or this may beaccomplished in other ways,) and to prevent any downward movement of thesame we preferably mount upon said rods the collars 33 and secure themby means of set-screws 34, adjacent to the top of the casing, as shown.The rod 24 preferably projects to a higher plane than the rod 25, andmountedrigidly upon their upper ends, so as to swing in parallelhorizontal planes, are the forwardly-projecting arms provided withhandles 35 and 36, respectively, at their outer ends, and said arms,which are preferably of spring metal, are provided with depending teeth35 and 36, respectively, to engage one of the notches or recesses a, b,or c of the segmental plates 37 and 38. Said plates may be supportedhorizontallyi n anysuitable or preferred manner, but the plate 37 mustbe arranged above the arm of the rod 25 and the plate 38 below said arm,as shown in Figs. 1 and 2. lVe preferably construct said plate as shownin the drawings-that is, form them integrally and clamp them upon thetop bar of the frame by a sleeve 39. They may obviously be secured inother ways, however, without departing from the spirit of our invention.

In the drawings we have shown the cogwheels 17, 18, and 21 of the samediameter and the cog-wheels 16, 19, and 22 of equal diameter. Thisproportion, however, may be varied as required.

As arranged in Figs. 4 and 2, the machine is geared to its normalspeed-that is, the large gear 21 upon the pedal-shaft drives the smallgear 16, and said gear in turn drives the large gear 18 upon thesprocket-wheel shaft, which in effect is practically the same as whenthe sprocket wheel is mounted upon the pedal-shaft direct, leaving outof consideration, of course, the friction in the gearing. At the sametime the depending teeth 35 and 36 engage the notches a of the plates 37and 38, respectively, as shown clearly in Fig. 2 by dotted lines.

When it is desired to lower the gear and therefore make it easier forthe rider to propel the machine uphill, the rider grasps the handle 36and swings it to the right until its tooth engages the notch c, and thiscauses, as will be readily understood, the cog-wheels 21 and 22 toassume the position shown in dotted lines, Fig. 4. The small cog-wheelin such position meshes with the large cog-wheel of the shaft 10. Themotion is transmitted from pedal-shaft to the sprocket-wheel by means ofthe cog-wheels 22 and 17 and 16 and 18, the small wheels driving thelarge wheels in both instances.

hen it is desired to increase the speed of the bicycle, supposing thegearing to be in the position shown in full lines, Fig. 4, the ridergrasps the handle 35 and moves it to the left until its tooth comes intoengagement with the notch c of the plate 37, and this causes, throughthe intermediate connections, the wheels 18 and 19 to slide to the leftupon the shaft 8 until the small wheel 19 meshes with the large wheel17. In this arrangement the power is transmitted from the pedal-shaft tothe sprocket-wheel shaft through the medium of the gear-wheels 21 and 16and 17 and 19, the large wheels driving the small wheels in both caseswith a consequent increase of speed. Supposing, when on a downgrade,that the rider desires to coast, he grasps either handle and minipulatesit until the teeth of the lever engage the middle notch. By so doing hethrows and holds, as the case may be, the wheels 21 and 22 or 18 and 19midway between the wheels 16 and 17 and entirely out of connection witheither. It is apparent that when in this position the foot may rest uponthe pedals without causing the latter to revolve. If the wheels 21 and22 are thus disengaged, the rotation of the drive-wheel will cause therotation of the shaft 10 through the medium of the interposed gearing,but if the wheels 18 and 19 are thus disengaged the remainder of thegearing within the casing, together with the pedals, will be stationary,as will be readily understood.

It will be noticed that access may be easily had to the gearing foroiling or other purposes by simply slipping upward the collars 33 uponthe rods 24: and 25 and then withdrawing the screw-bolts which hold thetop plate in position, when the latter may be raised. The preciseconstruction of the casing, however, is immaterial, as it is designedsimply as a means for protecting the gearing.

From the above description it is obvious that we have produced aspeed-gearing for bicycles which will be found exceedingly valuable,particularly for use where there are a great many hills and for touringpurposes, and that we have produced a gearing which combines suchdesirable features with extreme simplicity, strength, and durability ofconstruction at a comparatively small expense. It will also be noticedthat a machine provided with such gearing may be used for any kind ofservice, as there are no small parts to get out of place or to becomeinjured or broken.

It is to be understood, of course, that slight changes in the form,proportion, or arrangement of parts may be made without departin g fromthe spirit and scope of our invention.

Having thus described the invention, what we claim as new, and desire tosecure by Letters Patent, is

In a bicycle, the combination of a casing supported by the frame, ashaft journaled therein, and provided with shiftable gearwheels andgeared to the drive-wheel of the bicycle, a second shaft journaledtherein, and also provided with shift-able gear-Wheels and Withpedal-carrying cranks, an intermediate shaft provided with rigidgear-wheels, a removable top for said casing, vertical rods journaledtherein and inthe top bar of the bicycle-frame in advance of the seat,crankarms 26 secured to the lower end of said rods, forked clutchesembracing the opposite sides of said shiftable gear-wheels andadjustable upon said crank-arms, a clasp embracing the top bar of theframe in advance of said rods and provided with horizontalsegment-plates provided each with three notches, one of said JAMES W.BRASFIELD. JOSEPH H. JENKINS.

Witnesses:

E. B. THATCHER, JAooB lVICFALL.

